July 11, 2015

Irritable bowel syndrome (IBS) is an often misunderstood and underdiagnosed condition that affects about 15.3 million people in the United States.

No one remedy works for all patients, so there’s a great medical need to develop new therapies for IBS, says Andrew Mulberg, M.D., a gastroenterologist with the Food and Drug Administration (FDA). That’s why FDA is working to bring more treatments to the market.

“There’s a lot of new research about the role of carbohydrates, and specifically a nutrient called polyols, in triggering irritable bowel syndrome in some patients,” Mulberg says. “In addition, doctors, scientists and researchers are more closely examining the role of diet in IBS causes and treatments.”

What Is IBS?

IBS is a gastrointestinal disorder that affects the large intestine (colon) but doesn’t cause inflammation or permanent damage. Common symptoms of IBS include:

Diarrheas

Constipation

Abdominal pain, bloating or cramping

Gas

Mucus in the stool

The symptoms may come and go, and can change in the same patient. Sometimes the pain from IBS can be so severe that it’s disabling and patients can’t do routine things. In addition, severe diarrhea can lead to dehydration and an electrolyte imbalance.

Doctors don’t know what causes IBS, and there is no known cure. Studies estimate that as many as 20% of Americans suffer from IBS. Many people may not know they have this gastrointestinal disorder. They might have occasional diarrhea and constipation and think it’s caused by something they ate, or a virus, so they don’t see a doctor to get a proper diagnosis. When they do, doctors must first rule out that the symptoms aren’t caused by a disease or another condition.

“There are many conditions that have a female or male predominance, but we don’t understand why women have a higher prevalence of IBS,” says Mulberg, deputy director of FDA’s Division of Gastroenterology and Inborn Errors Products (DGIEP).

IBS is most common among people younger than 45, and patients usually first experience symptoms when they’re in their late 20s. People who have a family history of IBS are also more likely to develop the condition.

Depression, anxiety and other psychological problems are common in people with IBS, Mulberg says.

“Some people suffer from depression and IBS. The question is what’s primary or secondary – what came first?” he says. “Either way, antidepressants are not a cure for IBS.”

What You Can Do

Treatments for IBS vary from patient to patient and include changes in diet, nutrition and exercise. Some patients need stool softeners to treat constipation; others need antidiarrheal drugs to treat diarrhea.

“IBS is not like other chronic conditions, such as hypertension, which is constant. IBS is a variable condition. Even without treatment, the problem might go away in some patients. But the symptoms might return after a few months,” says Ruyi He, M.D., an internist and medical team leader with DGIEP.

No one medication works for all people suffering from IBS.

Most recently, FDA approved Linzess (linaclotide) to treat some adults who suffer from IBS with constipation and for chronic idiopathic constipation. Chronic idiopathic constipation is a diagnosis given to those who experience persistent constipation and do not respond to standard treatment. According to the National Institutes of Health, about 63 million people have chronic constipation.

In addition, FDA has approved Amitiza (lubiprostone) for IBS with constipation and one drug for IBS with diarrhea, Lotronex (alosetron).

“Drugs are a last option. Patients should try diet and lifestyle changes, especially exercise, before resorting to medication,” He says.

Certain foods and drinks can trigger IBS symptoms in some patients. The most common are foods rich in carbohydrates, spicy or fatty foods, milk products, coffee, alcohol and caffeine.